An electronic control device which houses a circuit board mounted with an electronic component has been used in a variety of industrial technical fields. Particularly, a technique for fixing the circuit board is important in an industrial technical field to which mechanical external force, such as vibration, or thermal stress is applied.
For example, an intake system configuration member of an internal combustion engine mounted on an automobile is configured by combining many submodules, such as an air cleaner, an intake duct, an air flow sensor, a throttle body, and an intake manifold. Moreover, in recent years, in addition to sensors and actuators mounted on the respective submodules, there have been increasing number of examples in which an electronic control device which used to be disposed in a cabin hitherto is mounted within a hood of the automobile. Moreover, this electronic control device is configured to be fixed to another component within the hood of the automobile by a screw or the like.
Incidentally, the component within the hood is in an extremely severe installation environment by receiving vibration from the internal combustion engine or vibration based on running of the automobile. Accordingly, a circuit board disposed within the electronic control device is affected by this vibration and strongly receives mechanical external force. Further, a material, such as a resin, is used for this type of electronic control device to reduce a unit cost of production, and the electronic control device adopts a structure in which the circuit board is fixed therein without using an extra fixing means, such as a screw.
As such an electronic control device, for example, JP 2006-19674 A (PTL 1) discloses a case structure of an electronic control device including a circuit board mounted with an electronic component, a case body (a case) which is formed in a box shape with one open surface and has a guide groove part for inserting the circuit board on each internal side surface, and a lid (a cover) for covering the open surface of the case body. The circuit board is held in an internal space formed with the case body and the lid.